Two-Material P&A Plug for Contamination-Resistant Well Sealing
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Solution Overview
Problem
Current plug and abandonment (P&A) operations face challenges with cement and resin plugs due to contamination, time-consuming setting processes, and high costs, particularly in creating effective rock-to-rock seals and maintaining well integrity.
Innovation Solution
A two-material plug combining a eutectic alloy, preferably bismuth-based, and resin, where the alloy forms a base seal and the resin adheres to form a redundant sealing mechanism, reducing the need for longer plugs and minimizing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement plugs are used for well abandonment, then sealing capability is provided, but contamination by mud occurs resulting in placement issues and plug failure
Solution Approach 1:
The patent uses a composite plug material consisting of a metal base material (such as bismuth alloy) combined with resin. The metal base provides structural integrity and resistance to contamination, while the resin provides sealing capability through adhesion. This composite structure eliminates the contamination issues associated with cement while maintaining effective sealing.
Solution Approach 2:
The patent changes the physical and chemical parameters of the plug material by using a metal base material that is immiscible with well fluids, preventing contamination. The metal base is heated to melt it, allowing it to flow and seal the wellbore, then solidifies to provide a stable foundation for the resin seal.
2Reliability
If resin plugs are used instead of cement, then resistance to chemicals and mechanical properties improve, but setting time increases and complex chemistry is required
Solution Approach 1:
The patent applies preliminary action by first placing the metal base material in the wellbore and heating it to melt and seal the wellbore before adding the resin. This preliminary sealing action creates a stable foundation that eliminates the need for long setting times, as the resin can be set immediately on the pre-sealed metal base.
3Reliability
If longer cement plugs are used, then sealing coverage is improved, but cost and operational complexity increase
Solution Approach 1:
The composite metal and resin plug material provides effective sealing coverage with a shorter overall plug length. The metal base material provides structural integrity and sealing capability in a compact form, reducing the need for long plug lengths while maintaining effective sealing coverage.
4Reliability
If cast-in-place metal plugs are used, then sealing effectiveness improves, but heating time and equipment complexity increase
Solution Approach 1:
The patent segments the plug into two distinct materials: a metal base material that is heated and melted to seal the wellbore, and a resin component that is set on top of the metal base. This segmentation allows the metal to provide immediate sealing upon cooling, while the resin can be set separately without requiring extended heating time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The two-material plug provides a cost-effective, faster, and more reliable sealing solution, achieving a rock-to-rock seal with reduced material usage and lower operational costs, enhancing wellbore integrity and reducing failure probabilities.
Implementation Method 1
A eutectic alloy, such as an expandable bismuth alloy, is heated in place to form a molten liquid metal that easily penetrates small crevices and cracks, and hardens in place forming a tight plug
Implementation Method 2
heated in place to form a molten liquid metal that easily penetrates small crevices and cracks, and hardens in place forming a tight plug
Implementation Method 3
Resin seal by adhesion, and have resistance to many caustic and corrosive chemicals
Implementation Method 4
The specific gravity of the metal being much higher than any fluid, results in effective placement. A heater tool... can heat such cast-in place bismuth alloy plugs
Data Source
Figure 1
Figure 2
Figure 3A~4B
AI summary
A plug for Plug and Abandonment (P&A) operations and methods of use are described. The plug comprises a bismuth-based alloy and resin, allowing for sealing of an oil well using two different mechanisms with a shorter plug.